Aero-wave instrument for the measurement of the optical wave-front disturbances in the airflow around airborne systems

ABSTRACT

An aero-optical disturbance measurement system includes a mirror supported by a gimbal for receiving a light beam from a light emitting source, reflecting the light beam to a first periscope fold mirror and therefrom reflecting the light beam directly to a second periscope fold mirror. A first concave off-axis paraboloid mirror receives the light beam reflected from second periscope fold mirror and therefrom a first fold mirror receives the light beam reflected directly from first concave off-axis paraboloid mirror. A second fold mirror receives the light beam reflected directly from the first fold mirror. A second concave off-axis paraboloid mirror receives the light beam reflected directly from second fold mirror which reflects the light beam to a fast steering mirror. A fine tracker camera coupled to an embedded processer receives portion of light beam from fast steering mirror. Embedded processor controls movement of fast steering mirror and gimbal.

FIELD

This present disclosure generally relates to optical instrumentation andmore particularly to optical instrumentation for measuring of opticaldisturbances in an air flow field.

BACKGROUND

As aircraft fly at subsonic, transonic or supersonic speeds,aero-optical disturbances in the air flow field surrounding the aircraftare created by surfaces of the aircraft moving through the air. Theseaero-optical disturbances will vary for each shape of an aircraft and asthe aircraft changes speed, altitude and operational maneuvers. Athigher speeds, such as supersonic, aero-optical disturbances in the airflow field surrounding the aircraft will include not only wavefrontdisturbances but also shock boundaries. These aero-optical disturbancescreated in the air flow field will affect the performance and/oraccuracy of optical instrumentation which are carried by the aircraftand are used to receive optical data and/or emit optical energy.

The problems created by these aero-optical disturbances include trackingaccuracy of optical trackers, blurred image quality of surveillancesensors, imprecise pointing of laser systems and reduced beam quality oflaser energy propagated through the aero flow field containing theaero-optical disturbances. Gathering accurate spatial and temporal dataof these aero-optical disturbances from the flow field of the aircraftwill enable the design of high performance and accurate opticalequipment such as optical trackers, optical imaging, laser radar,precise aiming equipment for lasers and laser weapon systems. Withaccurate measured data of these disturbances from the air flow fielddesign criteria can be implemented into these devices to compensate forthe optical deviations created by these aero-optical disturbances.

There is a need to be able to measure and collect aero-opticaldisturbance data for each different shape of air craft. Moreover, sincethe aero-optical disturbances change for various speeds, altitudes andmaneuver configurations of the aircraft, the data will need to becompiled for changes in these parameters as well. Thus, to obtainreliable modeling data for a particular aircraft, measurements of theaero-optical disturbances would best be acquired through appropriateequipment for measuring and collecting such aero-optical data to besecured to the aircraft with the aircraft flown through these variationsof parameters of speed, altitude and while conducting various maneuvers.

The aero-optical disturbances to be measured and collected for variousaircraft, could include subsonic, transonic and supersonic speeds up toat least Mach 2. The measurements of the aero-optical disturbances areneeded for the aircraft operating in an altitude envelope ranging fromsea level to seventy-five thousand feet. Additionally, the measurementsof the aero-optical disturbances will be needed from the aircraftconducting various maneuvers which impart as much as 3 g of force on theaircraft. All of this data will need to be accurately measured in orderto provide reliable modeling for each aircraft that will eventuallycarry optical equipment, as discussed above.

In the past, aero-optic measurements had been obtained by using windtunnels or by using large aircraft in flight to create the air flowfields. The use of wind tunnels to replicate the high speeds of aparticular aircraft, and more particularly, supersonic speeds greaterthan Mach 1 presented complications. In particular, shock wavesimpacting a wall of the tunnel disrupt the replication and thereforefidelity of an aero-optical disturbance that would normally occur inopen ambient air flow field flight. Because measurement equipment foraero-optical disturbances are generally large and complex equipment,larger aircraft have been needed to carry the equipment. The use oflarger aircraft also presented an additional problem with their limitedspeed ranges. With the limited speed of these larger aircraft, measuringaero-optical disturbances at higher rates of speed were limited if notcompletely prevented. Moreover, the large complex instrumentation formeasuring the aero-optic disturbances restricted the positioning orlocation of such equipment on the aircraft, thereby limiting thecollection of data of air flow field disturbances to the limitedpositions on the aircraft to accommodate the large complex equipment.

In order to measure and compile the needed data regarding the aero-opticdisturbances to provide modeling design criteria for opticalinstrumentation, measuring instrumentation needs to be developed that iscompact. Compact measuring instrumentation can be secured to smalleraircraft such as fighter aircraft that can travel at a wide range ofspeeds from subsonic to supersonic. Also, a compact configuration willenable the measuring equipment to be secured to numerous differentpositions on the aircraft. This will enable measurements to be made frompositions which would replicate the positions in which opticalinstrumentation may be later positioned. The compact size will also helpto prevent creating unwanted aerodynamic imbalance of the aircraft.

A compact configuration of the measuring instrumentation will facilitatethe measuring and collection of disturbance data for many differentaircraft that will need to travel through a wide range of speeds andaltitudes as well as with moving through various maneuvers. The compactconfiguration of the measuring equipment will provide the needed spatialand temporal data of the aero-optical disturbances in the flow field ofthat aircraft so as to establish the modeling in order to design theoptical systems and/or flow control devices the aircraft will ultimatelycarry to operate within and/or mitigate these aero-optical disturbances.

The features, functions, and advantages that have been discussed can beachieved independently in various embodiments or may be combined in yetother embodiments further details of which can be seen with reference tothe following description and drawings.

SUMMARY

An object of the present invention is to provide an aero-opticaldisturbance measurement system which includes a mirror supported by agimbal for receiving a light beam from a light emitting source andreflecting the light beam emitted from the light emitting source to afirst periscope fold mirror and a second periscope fold mirrorpositioned to receive the light beam reflected directly from the firstperiscope fold mirror. The measurement system further includes a firstconcave off-axis paraboloid mirror positioned to receive the light beamreflected from the second periscope fold mirror, a first fold mirrorpositioned to receive the light beam reflected directly from the firstconcave off-axis paraboloid mirror, a second fold mirror positioned toreceive the light beam reflected directly from the first fold mirror anda second concave off-axis paraboloid mirror positioned to receive thelight beam reflected directly from the second fold mirror and reflectingthe light beam to a fast steering mirror. Additionally included is afine tracker camera coupled to an embedded processer wherein the finetracker camera receives a transmitted portion of the light beam from thefast steering mirror, wherein the embedded processor is coupled to thefast steering mirror such that the embedded processor controls movementof the fast steering mirror and wherein the embedded processor iscoupled to the gimbal and controls the movement of the mirror supportedby the gimbal.

Another object of the present invention is to provide an aero-opticaldisturbance measurement system which includes a mirror supported by agimbal for receiving a light beam from a light emitting source andreflecting the light beam emitted from the light emitting source to afirst periscope fold mirror. A second periscope fold mirror ispositioned to receive the light beam reflected directly from the firstperiscope fold mirror. A first concave off-axis paraboloid mirror ispositioned to receive the light beam reflected from the second periscopefold mirror. A first fold mirror is positioned to receive the light beamreflected directly from the first concave off-axis paraboloid mirror. Asecond fold mirror is positioned to receive the light beam reflecteddirectly from the first fold mirror. A second concave off-axisparaboloid mirror is positioned to receive the light beam reflecteddirectly from the second fold mirror and reflecting the light beam to afast steering mirror. A beam splitter receives the light beam reflecteddirectly from the fast steering mirror wherein the beam splitter splitsthe light beam into a transmitted portion and a reflected portion.

Another object of the present invention is to provide an aero-opticaldisturbance measurement system which includes a mirror supported by agimbal for receiving a light beam from a light emitting source andreflecting the light beam emitted from the light emitting source to afast steering mirror. A beam splitter receives the light beam reflecteddirectly from the fast steering mirror wherein the beam splitter splitsthe light beam into a transmitted portion and a reflected portion. Afine tracker camera is coupled to an embedded processer wherein the finetracker camera receives the transmitted portion of the light beam fromthe fast steering mirror, wherein the embedded processor is coupled tothe fast steering mirror such that the embedded processor controlsmovement of the fast steering mirror and wherein the embedded processoris coupled to the gimbal and controls the movement of the mirrorsupported by the gimbal.

The features, functions and advantages that have been discussed can beachieved independently in various embodiments or may be combined in yetother embodiments further details of which can be seen with reference tothe following description and drawings.

BRIEF SUMMARY OF THE DRAWINGS

FIG. 1 illustrates a perspective schematic view of an aircraft in a flowfield wherein representative optical beams pass through the flow fieldto the aircraft;

FIG. 2 illustrates a back elevation view of a schematic representationof an embodiment of the wavefront measuring system;

FIG. 3 illustrates a top plan view of a schematic representation ofaero-optical disturbance measurement system;

FIG. 4 illustrates a side elevation view of the schematic representationof the wavefront measuring system as shown in FIG. 2;

FIG. 5 is an enlarged exploded schematic cut away view of a front end ofa fighter aircraft with an enlarged view of an embodiment of a containedaero-optical wave disturbance measurement system of FIG. 3 secured tothe fighter aircraft;

FIG. 6 is a schematic perspective view of a fighter aircraft to which anembodiment of the aero-optical wave disturbance measurement system ofFIG. 1 will be secured;

FIG. 7 is a schematic front profile view of an aircraft depicting sensorlocation options for characterization of flow field;

FIG. 8A is a first panel view of utilizing a star as a light emittingsource for data collection while in straight and level flight forinitial star acquisition;

FIG. 8B is a second panel view of utilizing a star as a light emittingsource for data collection while the aircraft executes a maneuver;

FIG. 8C is a third panel view of utilizing a star as a light emittingsource for data collection while the aircraft resumes straight and levelflight off the original flight path;

FIG. 8D is a fourth panel view of utilizing a star as a light emittingfor data collection as the aircraft maneuvers to return to the originalflight path;

FIG. 9A is a first panel view of utilizing an aircraft beacon as a lightemitting source for data collection while in straight and level flightfor initial beacon acquisition;

FIG. 9B is a second panel view of utilizing an aircraft beacon as alight emitting source for data collection while the aircraft executes amaneuver;

FIG. 9C is a third panel view of utilizing an aircraft beacon as a lightemitting source for data collection while the aircraft resumes straightand level flight off the original flight path; and

FIG. 9D is a fourth panel view of utilizing an aircraft beacon as alight emitting source for data collection as the aircraft maneuvers toreturn to the original flight path after passing by the beacon emitter.

DESCRIPTION

The present invention now will be described more fully hereinafter withreference to the accompanying drawings, in which example implementationsare shown. The invention may be embodied in many different forms andshould not be construed as limited to the examples set forth herein.

In referring to FIG. 1, in flight aircraft 10, in this embodiment, is anF 18. Aircraft 10 creates an air flow field 12 as it passes through theatmosphere. Disturbances are created in air flow field 12 as surfaces 14of aircraft 10 impact the air. Surfaces 14 include all external surfacesassociated with aircraft 10 that is exposed to air flow field 12, asseen in FIGS. 1 and 6. Such surfaces include fuselage 15, wings 17, tailsection 19, cockpit 21 etc. as well as all other external surfacesassociated with aircraft 10 including items appended to aircraft 10 suchas weapons and the like. As surfaces 14 vary in configuration withdifferent aircraft 10 the resulting aero-optical disturbances createdwithin air flow field 12 will differ in shape and distance from aircraft10. These aero-optical disturbances will be further altered as aircraft10 varies its speed and altitude and as aircraft 10 proceeds throughvarious maneuvers.

It should be understood that depending on the shape of surface 14 overwhich portions of air flow field 12 flows, the speed of the moving airmay differ. For example, if surface 14 is cambered the air flow will befaster over the cambered surface 14 than over a flatter surface 14.Thus, air speed on some portions of air craft 10 may be traveling, forexample, at supersonic speed in contrast to air speeds at differentlocations on air craft 10 which may be traveling at a transonic speed.Thus, the resulting disturbances in flow field 12 about air craft 10 arenot necessarily homogeneous or uniform from one location on aircraft 10to another.

As aircraft 10 flies at subsonic to transonic and into supersonicspeeds, the air in air flow field 12 will experience compression fromsurfaces 14 of aircraft 10. For example, compression of the air atsupersonic speeds creates shock waves/boundaries 18 with regions ofcontinuous flow 16 between the shock waves/boundaries in theaero-optical disturbances in air flow field 12. These disturbances arecreated outwardly from surfaces 14 of aircraft 10 as represented, forexample, schematically by alternating regions of shock waves/boundaries18 and continuous flow regions 16. Over curved surfaces multiple, weakershock waves/boundaries 18, coalesce into a stronger shock wave/boundary18, as seen in FIG. 1. The disturbances will take on variousconfigurations and will also vary in distance from aircraft 10 as speed,altitude and maneuver configurations of this particular aircraft 10vary.

These disturbances inclusive of the shock waves/boundaries 18 and thecontinuous flow regions 16 in air flow field 12 will affect optical pathreception and transmission by optical equipment carried by aircraft 10.Examples of paths of optical path transmission or reception areschematically shown as paths 20 and 22, in FIG. 1. The optical equipmentor devices on board aircraft 10 associated with these opticaltransmissions or receptions may include, for example, optical trackers,surveillance sensors, laser-aiming systems and laser-energy-propagatingweapons. In order for these devices to operate accurately, effectivelyand efficiently, they will need to reliably compensate for optical pathvariations caused by the disturbances within air flow field 12 asaircraft 10 flies through the atmosphere. A major step in accomplishingthis goal of reliable performance is to acquire reliable measurements ofthe aero-optical disturbances in air flow field 12 so as to incorporatesuch measurement data into the design of these optical pieces ofequipment.

In referring to FIGS. 2-4, an embodiment of aero-optical disturbancemeasurement system 24 is shown that can be mounted on aircraft 10 toacquire the needed data by spatially and temporally measuring theposition and contour of the aero-optical disturbances created by flightof aircraft 10 in air flow field 12. System 24, as seen in FIG. 3, inthis embodiment, includes wavefront measuring system 26 and gimbaledmirror system 28. An example of each of these systems 26 and 28 will bediscussed in detail herein as will their operation.

With aero-optical disturbance measurement system 24 secured to aircraft10, measurement data of the optical disturbance in air flow field 12will be acquired by receiving and analyzing a light beam that hastraveled through the optical disturbance before reaching aircraft 10.For purposes of this embodiment, light emitting sources such as a star,a beacon from another aircraft, a beacon from a ground source, a laserguide star or an artificial star may be selected for use by system 24.The light source needs to be sufficiently strong enough to operate withsystem 24 such that, for this embodiment, system 24 is configured towork with a light beam source or star with a visual magnitude of (Mv-′3)or brighter.

In referring to FIGS. 2-4, light beam 30, as seen in FIG. 3, originatesfrom a light emitting source, such as, in this embodiment, a star andenters gimbaled mirror system 28, as seen in FIG. 3, impacting mirror 32supported by gimbal 34. Mirror 32 reflects light beam 30 directly tofirst periscope fold mirror 36. In this embodiment, this gimbaled mirrorsystem 28 is a known as Cast Glance Gimbal, originally manufactured byHughes Optical Systems in 1974, and is currently being manufactured byThe Boeing Company. It has been utilized for both the missile and targettracking by the U.S. Navy and installed on the NP3D Aircraft.

This gimbaled mirror system 28 has been modified in this embodiment toinclude a gyro sensor 38 such as a dual axis DSP-1750/Digital Outputfiber optic gyro, manufactured by KVH Industries of Middleton, R.I. Gyrosensor 38 is coupled to mirror 32 and senses movement of mirror 32during flight based on movement of aircraft 10 and communicates thismovement to embedded processor 39, embedded in and coupled to finetracker camera sensor 41. In turn, embedded processor 39 is coupled togimbal support 34 and communicates corrective movements to be made bygimbal support 34 to mirror 32 to keep light beam 30 aligned with mirror32 as aircraft 10 moves in flight. More details as to embedded processor39, its coupling with gimbaled support 34 and the movements imparted tomirror 32 be will be discussed below.

With system 24 secured to aircraft 10 traveling at speeds up to andbeyond Mach 1 and conducting maneuvers, light beam 30 would otherwisemove out of alignment with mirror 32 or otherwise out of the field ofregard of mirror 32, unless corrective movements were made to mirror 32to compensate for the movement made by aircraft 10 in its maneuvers. Forexample, with aero-optical disturbance measurement system 24 secured toaircraft 10 to acquire aero-optic disturbance measurements and withaircraft 10 flying through a maneuver, mirror 32 moves relative to lightbeam 30. Gyro sensor 38 senses this movement of mirror 32 and sends thismovement data or information to embedded processor 39. Gyro sensor 38has a bandwidth connection range of 10 Hz to 100 Hz with embeddedprocessor 39. Embedded processor 39, in return, commands gimbal support34 to move mirror 32 to keep light beam 30 in proper alignment withmirror 32. Gimbal 34 operates with an angular sensing of <4 microradiansin resolution over a field of regard of +/−45 degrees in azimuth andelevation, and a maximum angular rate of >60 degrees/second in azimuthand elevation.

Embedded processor 39, as mentioned above, is coupled to a fine trackercamera 41, which will be discussed in more detail below. In thisembodiment, embedded processor includes: Field Programmable Gate Array(FPGA) such as the Xilinx Spartan-6 LX150T (with support for LX100T andLX75T); Boot Flash Memory; XMOS Supervisory Processor; 2×QDR-II SDRAM;Support for two 4×SDRAM interposer modules; NAND Flash providing 4GBytes of storage space; Sensor I/O supporting Camera Link; PCI-Express×1 Support; and 1 GbE to FPGA. Processor 39 further includes: GeneralPurpose Processor (GPP) such as Freescale QorIQ P1022; 512 Mbytes DDR3SDRAM with ECC; 12C RTC (via expansion IO); 12C Temperature Sensor;Serial Peripheral Interface (SPI) Configuration Flash; NAND Flashmemory; Processor Reset (via expansion IO); 10-bit communications linkbetween the FPGA modules supervisory processor (via expansion IO); PCIExpress ×1, Gen 1.0 to FPGA modules Spartan FPGA (via expansion IO);Gigabit Ethernet (via expansion IO); and Solid State Disk storage (viaexpansion IO). Embedded processor 39 is coupled to gimbal support 34with a bandwidth connection range of 10 Hz to 100 Hz. Gimbal support 34operates with a position sensing of <4 microradians in stroke over afield of regard of +/−45 deg in azimuth and elevation, and a maximumangular rate of >60 deg/sec in azimuth and elevation.

With embedded processor 39 receiving movement data with respect tomirror 32 from gyro sensor 38, embedded processor sends movementcommands to gimbal 34 to move mirror 32 and maintain mirror 32 properlypositioned to maintain light beam 30 from the light emitting source inthe field of regard for mirror 32 The Cast Glance actuators can drivethe gimbal with a maximum acceleration of >1700 deg/sec² in azimuth,and >400 deg/sec² in elevation.

Gimbaled mirror system 28 would also include, in this embodiment, use ofencoders between the stabilized platform, provided by gyro sensor 38,and the turning flat to enforce stabilized kinematics, as well as, a two(2) to one (1) encoder-synchronized drive between the stable platformand the turning flat. In addition, the gimbal uses rotational flexuresand rotary voice coils instead of bearings or commutated or brushed DCmotors.

With aero-optical disturbance measurement system 24 mounted to aircraft10, particularly one that can attain supersonic speed, high vibrationcan be imparted to gimbaled mirror system 28. In this embodiment, highlydamped passive isolators will be used on gimbal support 34.Additionally, at least a 100 Hz gyro stabilized loop can be employedutilizing gyro sensor 38 and gimbal support 34 to make correctivemovements to mirror 32 for large angle pointing to the light emittingsource, such as a star or other aircraft, etc. Moreover, use ofvibration data collected on a Boeing F-15E with a Shock Wave package at1.2 and 1.4 Mach can be input, for example, to a Simulink Model, orother model or simulation, of the gyro sensor 38 stabilized gimbal 34.The residual line of sight jitter is predicted to be less than 3.0microradians for base motion jitter. This allows the Fine Track sensor41, controlled by the embedded processor 39, to reduce the opticaldisturbance in the air flow field 12, by commanding correction to thefast steering mirror 54.

In this embodiment, first periscope fold mirror 36, of gimbaled mirrorsystem 28 receives light beam 30 directly from mirror 32 supported bygimbal 34 and reflects light beam 30 directly toward second periscopefold mirror 40 of wavefront measuring system 26, as shown in FIG. 3.Second periscope fold mirror 40 receives light beam 30 directly fromfirst periscope fold mirror 36 at, in this embodiment, a forty fivedegree (45°) angle of incidence. Second fold mirror 40 has, in thisembodiment, a four (4) inch minor axis ellipse with a broad band coatingof greater than ninety eight percent (98%) reflectivity. Light beam 30is reflected from second periscope fold mirror 40 directly to firstintermediate fold mirror 42. First intermediate fold mirror receiveslight beam 30 at, in this embodiment, a forty five degree (45°) angle ofincidence. First intermediate fold mirror 42 has a three (3) inch minoraxis ellipse with a broad band coating of greater than ninety eightpercent (98%) reflectivity. In turn, first intermediate fold mirror 42reflects light beam 30 directly to second intermediate fold mirror 44wherein second intermediate fold mirror 44 also receives light beam 30at, in this embodiment, a forty five degree (45°) angle of incidence.Similarly, second intermediate fold mirror 44 has, in this embodiment, athree (3) inch minor axis ellipse with a broad band coating of greaterthan ninety eight percent (98%) reflectivity.

Light beam 30 reflects from second intermediate fold mirror 44 directlyto first concave off-axis paraboloid mirror 46. First concave off-axisparaboloid mirror 46 has, in this embodiment, a broad band coating ofgreater than ninety eight percent (98%) reflectivity. Light beam 30 isreceived by first concave off-axis paraboloid mirror 46 at an angle ofincidence, in this embodiment, of less than eight degrees (8.0°). Lightbeam 30 reflects from first concave off-axis paraboloid mirror 46directly to first fold mirror 48. First fold mirror 48 is, in thisembodiment, a pupil relay with a broad band coating of greater thanninety eight percent (98%) reflectivity. Light beam 30 is received byfirst fold mirror 48 at an angle of incidence, in this embodiment, ofless than eight degrees (8.0°). Light beam 30 reflects directly fromfirst fold mirror 48 to second fold mirror 50 and is received by secondfold mirror 50 at an angle of incidence of, in this embodiment, of lessthan fifteen degrees (15.0°). Second fold mirror (50) is, in thisembodiment, also a pupil relay with a broad band coating of greater thanninety eight percent (98%) reflectivity.

Light beam 30 is reflected directly from second fold mirror 50 to secondconcave off-axis paraboloid mirror 52. Second concave off-axisparaboloid mirror 52 receives light beam 30 at an angle of incidence, inthis embodiment, of less than eight degrees (8.0°). Second concaveoff-axis paraboloid mirror 52, in this embodiment, is an off-axisparabola mirror pupil relay with a broad band coating of greater thanninety eight percent (98%) reflectivity. Light beam 30 reflects directlyfrom second concave off-axis paraboloid mirror 52 to fast steeringmirror 54 which is, in this embodiment, one inch (1″) in diameter with abroad band coating of greater than ninety eight percent (98%)reflectivity and a bandwidth of 100 to 1000 Hz.

Fast steering mirror 54, in this embodiment, is an OIM101 one inch FSM,manufactured by Optics In Motion LLC located in Long Beach, Calif. Faststeering mirror 54 is coupled to embedded processor 39 and fine trackercamera 41 to create a communication loop to provide fast steering mirror54 movement, with an angular stroke length within the range of +1.5degrees and −1.5 degrees and angular resolution of <2 microradian andoperates in a bandwidth connection with embedded processor 39 at 100 to1000 Hz, to compensate for jitter imparted to light beam 30 by flight ofaircraft 10. This jitter is created on the optical beam by the aircraft10 vibrations, and the aero-optical disturbances from the flow field 12,the shock wave 16, and the shock boundary 18 at various look anglesaround the aircraft. To create this communication loop, in part, faststeering mirror 54 is coupled to fine tracker camera 41 through atransmitted portion 58 of light beam 30. Light beam 30 reflects fromfast steering mirror 54, in this embodiment, directly to beam splitter56.

Beam splitter 56 has, in this embodiment, a one inch (1″) diameter witha broad band coating with a fifty percent (50%) reflectivity andreceives light beam 30 at an angle of incidence, in this embodiment, ofless than eight degrees (8.0°).

In this embodiment, beam splitter 56 is a broadband plate beam splittermanufactured by CVI Laser Optics of Albuquerque, N. Mex. This beamsplitter has a brand CVI Laser Optics with optical material: N-BK7glass; Surface Quality: 10-5 scratch and dig; Product Code: BBS;Adhesion and Durability: Per Mil-C-675C. insolvable in lab solvents;Clear Aperture: greater or equal to eighty five percent (85%) of centraldiameter; Coating Technology: Electron beam multilayer dielectric;Chamfer: 0.35 mm at forty five degrees (45°) (typical); Wedge: less thanor equal to five (5) arc min; Damage Threshold: one hundred (100) mJ/cm²for twenty (20) nsec, and twenty (20) Hz @one thousand sixty four (1064)nm; Thickness t+ or −0.25 mm; Diameter: ø+0/−0.25 mm; Surface Figure:λ/10 at 633 nm; Reflection: R_(unpolarized)=50%+ or −15%; and Coating onS2: Low-reflection Broadband Anti-Reflective coating. Beam splitter 56splits light beam 30 into a portion 58 and another portion 60.

A portion of light beam 30 which passes through beam splitter 56 isreferred to as transmitted portion 58 of light beam 30. Transmittedportion 58, in this embodiment, is received directly from beam splitter56 by f first tracker fold mirror 62 having, in this embodiment, a oneinch (1″) diameter with a broad band coating with greater than ninetyeight percent (98%) reflectivity. First tracker fold mirror 62 receivestransmitted portion 58 of light beam 30 at, in this embodiment, a fortyfive degree (45°) angle of incidence. Achromatic focusing lens 64 with abroad band AR coating receives transmitted portion 58 of light beam 30at normal or perpendicular angle of incidence. Second tracker foldmirror 66 has, in this example, a one inch (1″) diameter on thesemi-minor axis with a broad band coating with greater than ninety eightpercent (98%) reflectivity. Second tracker fold mirror 66 receivestransmitted portion 58 of light beam 30 from achromatic focusing lens 64at, in this example, a forty five degree (45°) angle of incidence andreflects transmitted portion 58 directly to filter wheel assembly 68associated with fine tracker camera 41 and positioned between secondtracker fold mirror 66 and fine tracker camera 41.

Filter wheel assembly 68 may be applied to optimize the signal from astar, in contrast, it may not be applied wherein the light emittinglight source may be a beacon carried by an aircraft. With transmittedportion 58 of light beam 30 passing through filter wheel assembly 68,transmitted portion 58 reaches fine tracker camera 41. Fine trackercamera 41 senses movement of transmitted portion 58 of light beam 30.

Fine tracker camera 41, in this embodiment, utilizes a Xenics Bobcat640CL Shortwave Infrared (SWIR) that is capable of 1700 Hz frame rate ina 128×128 windowed mode. With fine tracker camera 41 coupled to embeddedprocessor 39, with embedded processor 39 coupled to fast steering mirror54 and with fast steering mirror 54 coupled to fine tracker camera 41 byway of transmitted portion 58 of light beam 30, the communication loopis complete for fine tracker camera 41 to sense movement of transmittedportion 58 of light beam 30 and communicate that data to embeddedprocessor 39 which, in turns, sends commands to fast steering mirror 54to move fast steering mirror 54 accordingly. This communication loopwill operate to mitigate jitter imparted to aero-optical disturbancemeasurement system 24 by the high speed travel of aircraft 10.

Returning to beam splitter 56, beam splitter 56 divides light beam 30.Beam splitter 56 transmits a portion, transmitted portion 58, of lightbeam 30 and reflects another portion of light beam 30, now referred toas reflected portion 60, Reflected portion 60 is directed from beamsplitter 56 to first wave sensor fold mirror 70 having, in thisembodiment, a semi-minor axis diameter of one inch (1″) and with a broadband coating of greater than ninety eight percent (98%) reflectivity.Reflected portion 60 is received by fold mirror 70 at an angle ofincidence, in this embodiment, of less than fifteen degrees (15.0°) andreflects reflected portion 60 of light beam 30 directly to achromaticpupil relay 72 which, in this example, has a broad band AR coating.Reflected portion 60, in this embodiment, is received by achromaticpupil relay 72 at a normal angle of incidence.

Reflected portion 60 of light beam 30 passes on to wavefront sensorlenslet array 74 which are configured to capture spatial and temporalwavefront parameters associated with aero-optical disturbances createdby aircraft 10 in flow field 12. This would include shock boundaries 18with aircraft 10 traveling at various speeds inclusive of supersonic.Lenslet array 74 includes an array of lenslets of at least 16×16subapertures or a set of lenslets of 24×24 subapertures. In thisembodiment, wavefront sensor includes the Xenics Cheetah-640CL with24×24 sub-apertures with 5×5 pixels per sub-apertures in a 120×120window which would enable wavefront collection, in this example, at 15kHz. Lenslet array 74 focuses reflected portion 60 to a focal planearray wavefront camera 76. Wavefront camera 76 thereby receives temporaland spatial data of the aero-optical disturbances in flow field 12 fromreflected portion 60 of light beam 30 which has passed through wavefrontsensor lenslet array 74. Wavefront camera 76, in this embodiment,includes a 512×512 Short Wave Infrared focal plan and has a frame rateof greater than five (5) kHz.

Wavefront sensor lenslet array 74 and wavefront camera 76 are coupled tosensor power supply, which includes a signal interface and anotherembedded processor 78, which also includes a solid state data storagedevices such as, SAMSUNG 840 Pro Series MZ-7PD128BW 2.5″ 128 GB SATA IIIMLC Internal Solid State Drive (SSD). The solid state data storage willstore the temporal and spatial measured data of the aero-opticaldisturbances created by aircraft 10 received from the wavefront sensorlenslet array 74 and wavefront camera 76, along with, correspondingoperational or navigational data from aircraft 10. This stored data canthen be used to design optical instrumentation which will later beinstalled on aircraft 10. Additional equipment to support aero-opticaldisturbance measuring system 24, shown in FIGS. 2-4, includes gimbalelectrical interface port 80 and fast steering mirror power supply andcontroller 81.

The above described wavefront measuring system 26 and the gyrostabilized gimbaled mirror system 28 permit aero-optical disturbancemeasurement system 24 to be contained within a compact arrangement asseen in FIG. 5. For example, wavefront measuring system 26, without theCast Glance gimbal 28, can be assembled in an arrangement approximatelyeight inches (8″)×ten inches (10″)×twenty inches (20″) with a weight ofbetween thirty-four (34) and forty (40) pounds. With the Cast Glancegimbal 28, the dimensions are eight inches (8″)×nineteen inches(19″)×twenty inches (20″) with a weight of between one hundred seventy(170) and one hundred seventy five (175) pounds. With the ability toprovide wavefront measuring system 26 with this light weight and compactarrangement, the gyro-stabilized gimbaled mirror system 28 can besecured to system 26 and measurement system 24 can now be secured atmany different locations on aircraft 10. This compact arrangement willpermit measurement system 24 to be installed on smaller fighter aircraftthat can attain supersonic speeds and not disrupt the aerodynamics ofthe aircraft.

In referring to FIG. 5, wavefront measuring system 26 and the gyrostabilized gimbaled mirror system 28 are each contained withincontainers 85 and 83, respectively. Containers 83 and 85 are firmlysecured together to form container assembly 82. Container 83 includes afront side 84 which defines opening 86 and permits gimbaled mirrorsystem 28 to be exposed to incoming light, such as light beam 30. Withrespect to wavefront measuring system 26, it is housed within container85. Optical components within wavefront measuring system 26 are heldrigidly within back container 85 with a carbon foam composite structure(not shown) and mounted to a carbon fiber bench 87, as seen in FIG. 3.Containers 83 and 85 are typically constructed of aluminum with athermal isolator to match the coefficient of thermal expansion of theoptical bench.

With container assembly 82 assembled, it is ready to be secured toaircraft 10 with passive isolators such as Barry Isolator Series 1000,which meets the Mil-M-17185 environment spec with a temperature range of−65 degrees F. to +180 degrees F., and Mil-STD-167 vibrationspecification. As for example, container assembly 82 is secured to aside of nose barrel position 88, as seen in FIG. 5. As will be discussedin more detail, container assembly 82 will, in this embodiment, bepositioned at a number of locations on aircraft 10 to measure andcollect temporal and spatial data of aero-optical disturbances in airflow field 12 surrounding different portions of aircraft 10. Typicallycontainer assembly 82 containing aero-optical disturbance measuringsystem 24 will be positioned behind a window or conformal window 90 asshown in FIG. 5. Light beam 30 coming from a light emitting source suchas a star or another aircraft or ground location etc. will pass throughan aero-optical disturbance in air flow field 12, pass through window orconformal window 90 and then through opening 86 of container 83. Lightbeam 30 will then reflect off of mirror 32 supported by gimbal 34 andfirst periscope fold mirror 36 and into wavefront measuring system 26where light beam 30 is received by second periscope fold mirror 40. Onother occasions, container assembly 82 containing system 24 will besecured on an external portion of aircraft 10 behind a window which isnot a conformal window 90 or at other positions of aircraft 10 wherein aconformal window 90 is employed.

As seen in FIG. 6, this embodiment portrays an F-18 fighter aircraft 10.As discussed above, container assembly 82 will be secured to the F 18aircraft 10 and positioned, for example, behind conformal window 90 atlocations including: dorsal mid-body (two locations) 92; wing gunlocation 94; electro-optical targeting system 96 or on other aircraft alower gun bay; conformal fairing 98; upper nose barrel 100; and dorsalbehind cockpit 102. With measurement system 24 positioned at thesevarious locations, aero-optical disturbance data can be measured andcollected around aircraft 10. A single measurement system 24 may beemployed on aircraft 10 or multiple measurement systems 24. With thecollected measured data, modeling for optical equipment that will bepositioned at these various locations will be compiled to create designcriteria for the optical equipment to be able to accommodate opticaldeviations created by the aero-optical disturbances positioned in airflow field 12 of aircraft 10.

As seen in FIG. 7, in this embodiment aircraft 10 is an F 18 in flightand sectors about aircraft are demarked to indicate possible field ofregard of positions of measuring system 24 taking measurements withaircraft 10 in flight. In referring to FIG. 7, these sectors positionedabout aircraft 10 include top sensor field of regard 104; bottom sensorfield of regard 106; right hand sensor field of regard 108 and left handsensor field of regard 110. Regardless, of the positioning ofaero-optical disturbance measuring systems 24 on aircraft 10, the flightgeometries for the testing for acquisition of data will depend on thefield of regard of the optical system within system 24 and the locationand speed of the light emitting source.

To fully characterize the air flow field 12 around aircraft 10 wouldrequire the optical system field of regard to be 4π steradians whichwould require more than one sensor or system 24. Although multiplesystems 24 are possible to be secured to the top and bottom of aircraft10 this is not necessary for a characterization or data acquisitionflight. The air flow around aircraft 10 is substantially the same on theleft hand side field of regard 110 and the right hand side field ofregard 108. The differences in the air flow field 12 around aircraft 10will occur in top and bottom fields of regard 104 and 106.

Measurement system 24 should be in a position on aircraft 10 tocharacterize top 104 and bottom 106 of flow field 12. The betterposition for this would be on either side of the fuselage 15 of aircraft10 with sufficient field of regard to measure or characterize flow field12 above, below, side, forward and aft of aircraft 10. However, thelarger the field of regard also minimizes the required aircraft 10maneuvering to view the light emitter source, whether a star or anotheraircraft etc., and increases the available data collection time.However, the larger the field of regard, the larger the window orconformal window 90 will be needed.

Should window 90 be non-conformal and forms a blister, for example, onthe external surface of aircraft 10, will require a different gimbalmirror with greater field of regard. The blister configuration willchange the flow field 12 being measured. It is understood theaero-optical measuring system 24 comprising gimbal mirror system 28 andwavefront measuring system 26 can be secured to a wide variety ofaircraft that have a fuselage and at least one aerodynamic interfacesurface, such as, a fixed wing 17, stabilizing fin, rotary blade etc.and not be secured only to an airplane such as aircraft 10. The widevariety of aircraft, in addition to the airplane, would include, forexample, a rocket, missile, helicopter, aircraft that have fixed wingswith helicopter functionality capabilities etc. These aircraft wouldprovide a platform from which aero-optical measuring system 24 wouldmeasure aero-optical disturbances in the flow field surrounding thatparticular aircraft.

As mentioned above, the data measuring or characterization flights thatwill employ aero-optical disturbance measuring system 24, will use astar, or a beacon from another aircraft or from the ground etc. as itslight beam 30 source to pass through measuring system 24. System(s) 24will, in this embodiment, be secured within container assembly 82 and,in turn, be firmly secured to a desired location on aircraft 10. It iscontemplated that securement of system 24 behind conformal window 90will provide the least intrusion to air flow field 12, however, otherdata acquiring may cause system 24 to be secured behind a non-conformalwindow creating an anomalous surface on aircraft 10 affecting air flowfield 12.

Now referring to FIGS. 8A-8D, aero-optical disturbance measuring system24 was developed, in this embodiment, to fly on an aircraft 10 tomeasure and acquire aero optical disturbances in air flow fields ofaircraft 10, as shown. In particular, measuring system 24 was developedso as to be able to use system 24 on a smaller type aircraft, such as afighter aircraft, in order to be able to secure system 24 to multiplelocations on aircraft 10 without disrupting the aerodynamics of aircraft10 and to be able to acquire data in a wide range of air speedsincluding supersonic.

In an embodiment of a flight for measuring and acquiring aero-opticaldisturbance data, as shown in FIGS. 8A-8D, in this embodiment, an F-18aircraft 10 commences flying along a flight path 116 with measuringsystem 24 secured to a forward nose barrel position 100. In thisembodiment, aircraft 10 is traveling at 1.6 Mach at an altitude ofthirty thousand feet (30,000 ft). Measuring system 24 is operating at aninety degree (90°) full field of regard 112 and receives a light beam30 from a light emitting source, star 114, having a magnitude of Mv3 orbrighter. Light beam 30 is received by mirror 32 supported by the gimbal34, within a gyro stabilized gimbal mirror system 28. Light beam 30passes through wavefront measuring system 26 inclusive of fast steeringmirror 54 and through beam splitter 56. Beam splitter 56 splits lightbeam 30 into a transmitted portion 58 and a reflected portion 60.Transmitted portion 58 of light beam 30 is reflected, as describedabove, to fine tracker camera 41 which is coupled to embedded processor39. In turn, embedded processor 39 is coupled to gimbaled mirror system28 to control movement of mirror 32 supported by gimbal 34 and iscoupled to fast steering mirror 54 to control movement of fast steeringmirror 54.

With aircraft 10 flying, collecting data regarding aero-opticdisturbances in flow field 12 of aircraft 10 step is commenced.Wavefront sensor lens array 74 and wavefront sensor camera 76 measureaero-optical disturbance data from other portion 60 of light beam 30.Another embedded processor 79 coupled to wavefront sensor lens array 74and wavefront sensor camera 76, receives the measured aero-opticaldisturbance data and stores that data. As mentioned earlier, anotherembedded processor 78 is also coupled to aircraft 10 and receivesnavigational information regarding the aircraft 10 location, altitudeand ground speed as well.

Typically, prior to aircraft 10 taking off to measure and acquireaero-optical disturbance data, a light emitting source is selected, suchas star 114 in this example, which has sufficient visible magnitude tooperate with measurement system 24. The coordinates for the lightemitting source or star 114 are placed into the embedded processor 39that is coupled to fine tracker camera 41. This enables mirror 32supported by gimbal 34 to search and detect light emitting source orstar 114 with aircraft 10 in flight.

After engines are started, the crew of aircraft 10 initializes system 24and initializes inertial guidance system from the GPS of aircraft 10.Aircraft 10 proceeds to take off and heads for an initial point formeasuring and data acquisition. In this embodiment. set forth in FIGS.8A-8D, aircraft 10 attains a speed of 1.6 Mach at an altitude of thirtythousand feet (30,000 ft.) with a level flight path 116. The crewinitiates a data collection command which initiates gimbal 34, faststeering mirror 54, tracker camera 41 and embedded processor 39. Thepreloaded target coordinates provide guidance to the initiated devicesto acquire the preloaded coordinates for the light emitting source orstar 114. With light emitting source or star 114 having light beam 30engaged to mirror 32 supported by gimbal 34, fine tracker camera sensor41 sensing light beam 30 centered in the image field, with low bandwidthcommunication loops closed for gimbal 34 and fast steering mirror 54with embedded processor 39, measurement system 24 is prepared to entermeasurement and acquisition mode with respect to aero-opticaldisturbances within air flow field 12.

In FIG. 8A, aircraft 10 has attained altitude, speed, flight path andlight emitting source or star 114. Flight path 116 is straight andlevel. Tracker 41 detects sufficient signal obtained from transmittedportion 58 of light beam 30 from star 114, crew can close high bandwidthloop on fast steering mirror 54 and embedded processor 79 initiatescollecting the measured data from wavefront lens array 74 and camera 76measuring the aero-optical disturbance from reflected portion 60 oflight beam 30. The high bandwidth loop on fast steering mirror 54remains in this mode during measurement and data acquisition ofmeasurement system 24 so as to mitigate jitter affects that may beimparted to system 24 during such high speed travel of aircraft 10.During this process, when tracker 41 detects movement of transmittedportion 58 of light beam 30 and sends that data to embedded processor 39which, in turn, sends commands to fast steering mirror 54 to move. Inthe embodiment seen in FIG. 8A, star 114 appears at a twenty degree(20°) elevation from aircraft 10 and seventy degrees (70°) off of lefthand side of nose 120 of aircraft 10. Star 114 is up and forward inmeasurement system 24 field of regard.

In FIG. 8B, at ten seconds into the data measuring and acquisitioncommencement, the next step, in this embodiment, includes aircraft 10initiating moving its direction of flight or initiating a maneuver. Themaneuver is a forty degree (40°) bank turn at 1.6 Mach. This maneuvermoves star 114 down and aft in the field of regard for measurementsystem 24 and aircraft 10 toward a second flight path (not shown). Thismaneuver moves light emitting source or star 114 in gimbal 34 supportedmirror 32 field of regard. Gyro sensor 38 sends movement data of mirror32 to embedded processor 39. Embedded processor 39 sends commands togimbal 34 to move mirror 32 keeping light beam 30 aligned with mirror 32or in the proper field of regard for mirror 32. At the same time, otherreflected portion 60 of light beam 30 continues to enter wavefront lensarray sensor 74 and wavefront sensor camera 76 thereby measuringaero-optical disturbances from reflected portion 60 of light beam 30.These measurements are stored in embedded processor 78.

In this embodiment, at fifty seconds (50 secs.) after commencingmeasuring and acquiring data with respect to aero-optical disturbances,aircraft 10 rolls to level in FIG. 8C and commences flying in a secondflight path. At this point, aircraft 10 is still traveling at 1.6 Machat a straight and level configuration with star 114 at twenty degrees(20°) elevation from aircraft 10 and one hundred degrees (100°) off ofleft hand sector of nose 120. Star 114 is up and aft in field of regardfor measuring system 24. In this step of flying aircraft 10 in thesecond flight path, wavefront lens array sensor 74 and wavefront sensorcamera 76 continue to receive reflected portion 60 of light beam 30 inorder to measure aero-optical disturbance created by aircraft 10 in airflow field 12.

In referring to FIG. 8D, at sixty seconds (60 secs.) from the timemeasuring was initiated, aircraft 10 takes the next step of moving fromthe second flight path with a ten degree (10°) bank turn moving aircraft10 back to flight path 116. This maneuver moves star 114 up in measuringsystem 24 field of regard and moves forward in measuring system 24 fieldof regard. Communication loop of gyro sensor 38, embedded processor 39and gimbal 34 maintain star 114 image and light beam 30 aligned withfield of regard for mirror 32. Gyro sensor 38 senses movement and sendsthat data to embedded processor 39. Embedded processor in return sendscontrol commands to gimbal 34 to move mirror 32 and maintain star 114 inthe field of regard of mirror 32. During this step with moving aircraft10 back to flight path 116 reflected portion 60 of light beam 30continues to be received by wavefront lens array sensor 74 and wavefrontcamera 76 so as to continue to measure the aero-optical disturbance inair flow field 12. The measurement data continues to be stored byembedded processor 78.

At the completion of the maneuver by aircraft 10, the crew shuts off thehigh bandwidth communication loop of fast steering mirror 54 causingmeasurement data collection from embedded processor 78 to automaticallystop. Communications from embedded processor 39 to gimbal 34 and finetracker camera 41 are also disabled. The crew then flies aircraft 10 toits next measurement and acquisition initial or commencement point andthe process is repeated. Once all of the data is measured and collectedby system 24, for that particular flight mission, the ground crew offloads the data that was stored in embedded processor 78. These flightmissions are carried out until sufficient data has been measured andacquired for aero-optical disturbances in air flow field 12 for eachtype of aircraft 10 at various speeds, altitudes and flight maneuveringconfigurations.

The collecting of aero-optical disturbance data in air flow field 12 ofaircraft 10 was described above in FIGS. 8A-8D with using a star 114 asthe light emitting source for light beam 30. Similarly, such measurementdata of aero-optical disturbances is collected in FIGS. 9A-9D with thelight emitting source being a beacon on another aircraft 122 emittinglight beam 30. In FIG. 9A, in this embodiment, aircraft 10 is in itsfirst flight path 116 traveling at 1.6 Mach at an altitude of thirtythousand feet (30,000 feet) in straight and level flight. Light beam 30from other aircraft 122 is tracked and maintained in measurement system24 field of regard much like the flight associated with star 114.Aero-optical disturbances are measured and stored along with theoperational data from aircraft 10 by other embedded processer 78. Withlight emitting source acquired, measuring of aero-optical disturbancesproceed, in this embodiment, for fifteen seconds (15 secs.). The lightemitting source on other aircraft 122 is positioned at forty fivedegrees (45°) elevation from aircraft 10 and forty five degrees (45°)off the left hand side of nose 120 of aircraft 10. The target lightemitting source on other aircraft 122 is up and forward in measuringsystem 24 field of regard 112.

In referring to FIG. 9B, aircraft 10 commences moving or initiating abank turn. At about twenty seconds (20 secs.) from initially engaginglight emitting source, aircraft 10 continues to fly at 1.6 Mach andmakes a bank turn of forty degrees (40°). Target light emitting sourceis at forty eight degrees (48°) elevation from aircraft 10 and fiftyfour (54°) off nose 120 and moving aft. This bank moves target lightemitting source down and aft in measurement system 24 field of regard.Again, measurement and acquisition of aero-optical disturbance datacontinues as does maintaining the target light emitting source in thefield of regard of measurement system 24. Throughout the data measuringand acquisition, mitigating jitter is accomplished through the highspeed closed communication loop of the fast steering mirror 54 andembedded processor 39.

In referring to FIG. 9C, at thirty seconds (30 secs.) after initialengagement with beacon, aircraft 10 remains at 1.6 Mach and on astraight and level second flight path. Target light emitting source onother aircraft 122 is at one hundred degrees (100°) off of left side ofnose 120 of aircraft 10 and target beacon is up and aft in measurementsystem 24 field of regard 112. Again, measurement and acquisition ofthis data continues through reflected portion 60 of light beam 30 fromtarget light emitting source of other aircraft 122 passing throughwavefront lens array 74 and wavefront camera 76 and being stored onother processor 78.

In FIG. 9D, aircraft 10 has overcome other aircraft 122 at thirty nineseconds (39 secs.) after initial engagement with target light emittingsource. Aircraft 10 is still traveling at 1.6 Mach and makes a tendegree (10°) bank turn. Target light emitting source on other aircraft122 is forty four degrees (44°) up and one hundred and thirty sixdegrees (136°) aft from aircraft 10. Aircraft 10 has moved target lightemitting source up in measurement system 24 field of regard 112. Targetlight emitting source continues to move aft until out of measurementsystem 24 field of regard 112. Data measuring stops when pilot turns offmeasuring system 24. Again, the data stored by other processor 78 isoff-loaded by the ground crew once aircraft 10 returns to base.

As mentioned earlier, data measuring and collecting missions will, inthis embodiment, be run in a range of speeds of at least up to Mach 2,altitudes of sea level to seventy-five thousand (75,000 feet) and withmaneuvers up to 3 g. The measured and acquired data for airflow field 12aero-optical disturbances for each aircraft will provide custom modelingfor the optical equipment to be later carried by such aircraft.Incorporation of the spatial and temporal data measured by system 24will enable designs of the optical equipment to effectively compensatefor and operate through the aero-optical disturbances created in flowfields 12 of aircraft 10.

While various embodiments have been described above, this disclosure isnot intended to be limited thereto. Variations can be made to thedisclosed embodiments that are still within the scope of the appendedclaims.

What is claimed:
 1. An aero-optical disturbance measurement system,comprising: a mirror supported by a gimbal for receiving a light beamfrom a light emitting source and reflecting the light beam emitted fromthe light emitting source to a first periscope fold mirror; a secondperiscope fold mirror positioned to receive the light beam reflecteddirectly from the first periscope fold mirror; a first concave off-axisparaboloid mirror positioned to receive the light beam reflected fromthe second periscope fold mirror; a first fold mirror positioned toreceive the light beam reflected directly from the first concaveoff-axis paraboloid mirror; a second fold mirror positioned to receivethe light beam reflected directly from the first fold mirror; a secondconcave off-axis paraboloid mirror positioned to receive the light beamreflected directly from the second fold mirror and reflecting the lightbeam to a fast steering mirror; and a fine tracker camera coupled to anembedded processer wherein: the fine tracker camera receives atransmitted portion of the light beam from the fast steering mirror; theembedded processor is coupled to the fast steering mirror such that theembedded processor controls movement of the fast steering mirror; andthe embedded processor is coupled to the gimbal and controls themovement of the mirror supported by the gimbal.
 2. The aero-opticaldisturbance measurement system of claim 1, further including a gyrosensor coupled to the mirror supported by the gimbal so as to sensemirror motion wherein the gyro sensor is coupled to communicate movementof the mirror supported by the gimbal to the embedded processor.
 3. Theaero-optical disturbance measurement system of claim 2, wherein: themirror supported by the gimbal is positioned behind a window of anaircraft through which the light beam from the light emitting sourcepasses; and the window is positioned at different locations on theaircraft comprising at least one of a side nose barrel, a dorsalmid-body, a wing gun location, an electro-optical targeting systemlocation, a conformal fairing, an upper nose barrel and a dorsal behindcockpit.
 4. The aero-optical disturbance measurement system of claim 1,wherein the angle of incidence of the light beam with the firstperiscope fold mirror is approximately 45 degrees.
 5. The aero-opticaldisturbance measurement system of claim 1, further including a firstintermediate mirror fold mirror positioned to receive the beam of lightreflected directly from the second periscope fold mirror with an angleof incidence of approximately 45 degrees and reflects the beam directlyto a second intermediate fold mirror which receives the beam of light atapproximately 45 degrees of incidence.
 6. The aero-optical disturbancemeasurement system of claim 5, wherein the first concave off-axisparaboloid mirror receives the light beam directly reflected from thesecond intermediate fold mirror.
 7. The aero-optical disturbancemeasurement system claim 6, wherein a first fold mirror receives thebeam of light reflected directly from the first concave off-axisparaboloid mirror and reflects the beam of light directly to a secondfold mirror.
 8. The aero-optical disturbance measurement system of claim7, wherein a second concave off-axis paraboloid mirror receives thelight beam reflected directly from the second fold mirror.
 9. Theaero-optical disturbance measurement system of claim 1, wherein the faststeering mirror operates with an angular stroke length within a range of+1.5 degrees and −1.5 degrees and angular resolution of <2 microradiancommanded byte embedded processor with a control bandwidth of 100 Hz to1000 Hz.
 10. The aero-optical disturbance measurement system of claim 1,further including a beam splitter which receives the light beamreflected directly from the fast steering mirror wherein the beamsplitter splits the light beam into the transmitted portion and areflected portion.
 11. The aero-optical disturbance measurement systemof claim 10, further including a first tracker fold mirror receiving thetransmitted portion from the beam splitter and an achromatic lensreceives the transmitted portion of the light beam directly from thefirst tracker fold mirror and transmits the transmitted portion to thesecond tracker fold mirror.
 12. The aero-optical disturbance measurementsystem of claim 11, wherein the fine tracker camera receives thetransmitted portion reflected directly from the second tracker foldmirror.
 13. The aero-optical disturbance measurement system of claim 12,further including a filter wheel assembly positioned between the secondtracker fold mirror and the fine tracker camera.
 14. The aero-opticaldisturbance measurement system of claim 10, further including a firstwavefront sensor fold mirror receiving the reflected portion directlyfrom the beam splitter and directly reflecting the reflected portion toan achromatic pupil relay.
 15. The aero-optical disturbance measurementsystem of claim 14, further including a wavefront sensor comprising alenslet array positioned to receive the reflected portion directly fromthe achromatic pupil relay and focusing the reflected portion to a focalplane array camera.
 16. The aero-optical disturbance measurement systemof claim 15, wherein the array comprises a set of lenslets of at least16 by
 16. 17. The aero-optical disturbance measurement system of claim15, wherein the array comprises a set of lenslets of 24 by
 24. 18. Theaero-optical disturbance measurement system of claim 15, furtherincluding another embedded processor coupled to the wavefront sensorwhich collects data from the wavefront sensor and navigational datagenerated by an aircraft in which the disturbance measurement systemcontaining the wavefront sensor is configured to conformally mount tothe aircraft.
 19. The aero-optical disturbance measurement system ofclaim 15, wherein with the aero-optical disturbance measurement systemconfigured to conformally mount to an aircraft moving at a supersonicspeed on a flight path with the light beam received by the mirrorsupported by the gimbal in a field of regard for the mirror supported bythe gimbal, the tracker camera receives the transmitted portion of thelight beam and the wavefront sensor receives the reflected portion ofthe light beam.
 20. The aero-optical disturbance measurement system ofclaim 19, wherein with the aircraft moving away from the flight path,the light beam moves in the field of regard of the mirror supported bythe gimbal and the embedded processor provides control commands to thegimbal to move the mirror supported by the gimbal and the wavefrontsensor receives the reflected portion.
 21. The aero-optical disturbancemeasurement system of claim 20, wherein with the aircraft moving in asecond flight path, the wavefront sensor receives the reflected portion.22. The aero-optical disturbance measurement system of claim 21, whereinwith the aircraft moving to the flight path, the light beam moves withinthe field of regard for the mirror supported by the gimbal and the gyrosensor communicates that move to the embedded processor, and theembedded processor provides control commands to the gimbal to move themirror supported by the gimbal and the wavefront sensor receives datafrom the reflected portion.
 23. The aero-optical disturbance measurementsystem of claim 19, wherein a gyro sensor coupled to the mirrorsupported by the gimbal and to the embedded processor conveysinformation to the embedded processor regarding movement of the mirrorsupported by the gimbal and the embedded processor provides movementcommands to the gimbal to move the mirror supported by the gimbal. 24.The aero-optical disturbance measurement system of claim 19, furtherincluding the fine tracker camera detects movement of the transmittedportion and the embedded processor sends a command to the fast steeringmirror to move the fast steering mirror.
 25. The aero-opticaldisturbance measurement system of claim 1, wherein the embeddedprocessor is coupled to the gimbal with a control bandwidth of 10 Hz to100 Hz.
 26. The aero-optical disturbance measurement system of claim 1,wherein the gimbal operates with an angular sensing of <4 microradiansin resolution over a field of regard of +/−45 deg in azimuth andelevation, and a maximum angular rate of >60 deg/sec in azimuth andelevation.
 27. An aero-optical disturbance measurement system,comprising: a mirror supported by a gimbal for receiving a light beamfrom a light emitting source and reflecting the light beam emitted fromthe light emitting source to a first periscope fold mirror; a secondperiscope fold mirror positioned to receive the light beam reflecteddirectly from the first periscope fold mirror; a first concave off-axisparaboloid mirror positioned to receive the light beam reflected fromthe second periscope fold mirror; a first fold mirror positioned toreceive the light beam reflected directly from the first concaveoff-axis paraboloid mirror; a second fold mirror positioned to receivethe light beam reflected directly from the first fold mirror; a secondconcave off-axis paraboloid mirror positioned to receive the light beamreflected directly from the second fold mirror and reflecting the lightbeam to a fast steering mirror; and a beam splitter which receives thelight beam reflected directly from the fast steering mirror wherein thebeam splitter splits the light beam into a transmitted portion and areflected portion.
 28. The aero-optical disturbance measurement systemof claim 27, wherein the angle of incidence of the light beam with thefirst periscope fold mirror is approximately 45 degrees.
 29. Theaero-optical disturbance measurement system of claim 27, furtherincluding a first intermediate mirror fold mirror positioned to receivethe beam of light reflected directly from the second periscope foldmirror with an angle of incidence of approximately 45 degrees andreflects the beam directly to a second intermediate fold mirror whichreceives the beam of light at approximately 45 degrees of incidence. 30.The aero-optical disturbance measurement system of claim 29, wherein thefirst concave off-axis paraboloid mirror receives the light beamdirectly reflected from the second intermediate fold mirror.
 31. Theaero-optical disturbance measurement system claim 30, wherein a firstfold mirror receives the beam of light reflected directly from the firstconcave off-axis paraboloid mirror and reflects the beam of lightdirectly to a second fold mirror.
 32. The aero-optical disturbancemeasurement system of claim 31, wherein a second concave off-axisparaboloid mirror receives the light beam reflected directly from thesecond fold mirror.
 33. The aero-optical disturbance measurement systemof claim 27, further including a fine tracker camera coupled to anembedded processer wherein: the fine tracker camera receives thetransmitted portion of the light beam from the fast steering mirror; theembedded processor is coupled to the fast steering mirror such that theembedded processor controls movement of the fast steering mirror; andthe embedded processor is coupled to the gimbal and controls themovement of the mirror supported by the gimbal.
 34. The aero-opticaldisturbance measurement system of claim 33, further including a gyrosensor coupled to the mirror supported by the gimbal so as to sensemirror motion wherein the gyro sensor is coupled to communicate movementof the mirror supported by the gimbal to the embedded processor.
 35. Theaero-optical disturbance measurement system of claim 34, wherein: themirror supported by the gimbal is positioned behind a window of anaircraft through which the light beam from the light emitting sourcepasses; and the window is positioned at different locations on theaircraft comprising at least one of a side nose barrel, a dorsalmid-body, a wing gun location, an electro-optical targeting systemlocation, a conformal fairing, an upper nose barrel and a dorsal behindcockpit.
 36. The aero-optical disturbance measurement system of claim33, wherein the fast steering mirror operates with an angular strokelength within a range of +1.5 degrees and −1.5 degrees and angularresolution of <2 microradian commanded byte embedded processor with acontrol bandwidth of 100 Hz to 1000 Hz.
 37. The aero-optical disturbancemeasurement system of claim 33, further including a first tracker foldmirror receiving the transmitted portion from the beam splitter and anachromatic lens receives the transmitted portion of the light beamdirectly from the first tracker fold mirror and transmits thetransmitted portion to a second tracker fold mirror.
 38. Theaero-optical disturbance measurement system of claim 37, wherein thefine tracker camera receives the transmitted portion reflected directlyfrom the second tracker fold mirror.
 39. The aero-optical disturbancemeasurement system of claim 38, further including a filter wheelassembly positioned between the second tracker fold mirror and the finetracker camera.
 40. The aero-optical disturbance measurement system ofclaim 33, wherein the embedded processor is coupled to the gimbal with acontrol bandwidth of 10 Hz to 100 Hz.
 41. The aero-optical disturbancemeasurement system of claim 40, wherein the gimbal operates with anangular sensing of <4 microradians in resolution over a field of regardof +/−45 deg in azimuth and elevation, and a maximum angular rate of >60deg/sec in azimuth and elevation.
 42. The aero-optical disturbancemeasurement system of claim 27, further including a first wavefrontsensor fold mirror receiving the reflected portion directly from thebeam splitter and directly reflecting the reflected portion to anachromatic pupil relay.
 43. The aero-optical disturbance measurementsystem of claim 42, further including a wavefront sensor comprising alenslet array positioned to receive the reflected portion directly fromthe achromatic pupil relay and focusing the reflected portion to a focalplane array camera.
 44. The aero-optical disturbance measurement systemof claim 43, further including: another embedded processor coupled tothe wavefront sensor which collects data from the wavefront sensor andnavigational data generated by an aircraft; and the disturbancemeasurement system containing the wavefront sensor is configured toconformally mount to the aircraft.
 45. The aero-optical disturbancemeasurement system of claim 43, wherein the array comprises a set oflenslets of at least 16 by
 16. 46. An aero-optical disturbancemeasurement system, comprising: a mirror supported by a gimbal forreceiving a light beam from a light emitting source and reflecting thelight beam emitted from the light emitting source to a fast steeringmirror; a beam splitter which receives the light beam reflected directlyfrom the fast steering mirror wherein the beam splitter splits the lightbeam into a transmitted portion and a reflected portion; and a finetracker camera coupled to an embedded processer wherein: the finetracker camera receives the transmitted portion of the light beam fromthe fast steering mirror; the embedded processor is coupled to the faststeering mirror such that the embedded processor controls movement ofthe fast steering mirror; and the embedded processor is coupled to thegimbal and controls the movement of the mirror supported by the gimbal.47. The aero-optical disturbance measurement system of claim 46, furtherincludes: a first periscope fold mirror receiving the light beam sourcedirectly from the mirror supported by the gimbal; a second periscopefold mirror positioned to receive the light beam reflected directly fromthe first periscope fold mirror; a first concave off-axis paraboloidmirror positioned to receive the light beam reflected from the secondperiscope fold mirror; a first fold mirror positioned to receive thelight beam reflected directly from the first concave off-axis paraboloidmirror; a second fold mirror positioned to receive the light beamreflected directly from the first fold mirror; and a second concaveoff-axis paraboloid mirror positioned to receive the light beamreflected directly from the second fold mirror and reflecting the lightbeam to the fast steering mirror.
 48. The aero-optical disturbancemeasurement system of claim 47, wherein the angle of incidence of thelight beam with the first periscope fold mirror is approximately 45degrees.
 49. The aero-optical disturbance measurement system of claim47, further including a first intermediate mirror fold mirror positionedto receive the beam of light reflected directly from the secondperiscope fold mirror with an angle of incidence of approximately 45degrees and reflects the beam directly to a second intermediate foldmirror which receives the beam of light at approximately 45 degrees ofincidence.
 50. The aero-optical disturbance measurement system of claim49, wherein the first concave off-axis paraboloid mirror receives thelight beam directly reflected from the second intermediate fold mirror.51. The aero-optical disturbance measurement system claim 50 wherein afirst fold mirror receives the beam of light reflected directly from thefirst concave off-axis paraboloid mirror and reflects the beam of lightdirectly to a second fold mirror.
 52. The aero-optical disturbancemeasurement system of claim 51 wherein a second concave off-axisparaboloid mirror receives the light beam reflected directly from thesecond fold mirror.
 53. The aero-optical disturbance measurement systemof claim 46 wherein the fast steering mirror operates with an angularstroke length within a range of +1.5 degrees and −1.5 degrees andangular resolution of <2 microradian commanded byte embedded processorwith a control bandwidth of 100 Hz to 1000 Hz.
 54. The aero-opticaldisturbance measurement system of claim 46, further including a firsttracker fold mirror receiving the transmitted portion from the beamsplitter, an achromatic lens which receives the transmitted portion ofthe light beam directly from the first tracker fold mirror to a secondtracker fold mirror.
 55. The aero-optical disturbance measurement systemof claim 54, wherein the fine tracker camera receives the transmittedportion reflected directly from the second tracker fold mirror.
 56. Theaero-optical disturbance measurement system of claim 55, furtherincluding a filter wheel assembly positioned between the second trackerfold mirror and the fine tracker camera.
 57. The aero-opticaldisturbance measurement system of claim 46, further including a gyrosensor coupled to the mirror supported by the gimbal so as to sensemirror motion, wherein the gyro sensor is coupled to communicatemovement of the mirror supported by the gimbal to the embeddedprocessor.
 58. The aero-optical disturbance measurement system of claim46, wherein: the mirror supported by the gimbal is positioned behind awindow of an aircraft through which the light beam from the lightemitting source passes; and the window is positioned at differentlocations on the aircraft comprising at least one of a side nose barrel,a dorsal mid-body, a wing gun location, an electro-optical targetingsystem location, a conformal fairing, an upper nose barrel and a dorsalbehind cockpit.
 59. The aero-optical disturbance measurement system ofclaim 46, wherein the embedded processor is coupled to the gimbal with acontrol bandwidth of 10 Hz to 100 Hz.
 60. The aero-optical disturbancemeasurement system of claim 46, wherein the gimbal operates with anangular sensing of <4 microradians in resolution over a field of regardof +/−45 deg in azimuth and elevation, and a maximum angular rate of >60deg/sec in azimuth and elevation.
 61. The aero-optical disturbancemeasurement system of claim 46, further including a first wavefrontsensor fold mirror receiving the reflected portion directly from thebeam splitter and directly reflecting the reflected portion to anachromatic pupil relay.
 62. The aero-optical disturbance measurementsystem of claim 61, further including a wavefront sensor comprising alenslet array positioned to receive the reflected portion directly fromthe achromatic pupil relay and focusing the reflected portion to a focalplane array camera.
 63. The aero-optical disturbance measurement systemof claim 62, further including: another embedded processor coupled tothe wavefront sensor which collects data from the wavefront sensor andnavigational data generated by an aircraft; and the disturbancemeasurement system containing the wavefront sensor is configured toconformally mount to an aircraft.
 64. The aero-optical disturbancemeasurement system of claim 62, wherein the array comprises a set oflenslets of at least 16 by 16.